The invention concerns a parallelepipedal package, especially one made of a composite of cardboard and plastic, for liquids, soups, and similar products, with a front wall 1, a rear wall 2, and two side walls 3 and 4, with a square or rectangular top wall 5 and a square or rectangular bottom wall 6, and with its edges 14 and 15 drawn in to create at least one convex area.
A parallelepipedal package of this type is known from German Patent 1 215 576. The point of departure for the known package is the realization that, when it is made out of a relatively thin material in a parallelepipedal shaping cell, it tends to buckle out at the bottom and collapse at the top. The buckling out at the bottom is due to the weight of the product in the package, and the collapse at the top derives from the package being so tightly welded that the bottom draws the top in when it buckles. Packages in this condition are unattractive and are not strong enough to resist squeezing. The aforesaid German patent accordingly proposes making the side walls of the package slightly convex and drawing the longitudinal edges in while keeping the top and bottom walls precisely rectangular in order to plump the package out from top to bottom and make it strong enough to resist squeezing, whereby the perimeter of the package will remain constant in all horizontal sections. This approach accordingly involves consciously exhausting the deformation potential of the packaging material from the very beginning within limits dictated by the dimensional stability of the top and bottom walls due to the slight convexity at the top and bottom of the side walls of the package to the extent that further buckling at the bottom and hence drawing in of the side walls at the top will no longer be possible because it will be counteracted by the volume of the product at the top of the package slightly exceeding that of the parallelepiped.